1. Field of the Invention
This invention relates to a thin novel prescription lens, which is manufactured flat but is being used arched, curved, concaved, or convexed, and a method which the design is synthesized from its specification.
2. Terms Definition
The term xe2x80x9ceyewearxe2x80x9d as used herein is defined as any light-transmitting element or elements in front of the eyes.
The term xe2x80x9cprescriptionxe2x80x9d as used herein is defined as a specific combination of optical parameters that meets the needs of a particular person in purpose to solve a large variety of treatments and diagnostic problems known to eye specialists, or the required optical function/properties whenever the article is not an ophthalmic lens.
The term xe2x80x9cThieberger-design-lensxe2x80x9d as used herein is defined as the novel lens of my Co-Pending PCT Patent xe2x80x9cApplication xe2x80x9cOphthalmic lens synthesized from its specificationsxe2x80x9d, date Aug. 31, 1998 Number PCT/IL98/00420, incorporated herein by reference.
The term xe2x80x9cflat-Thieberger-design-lensxe2x80x9d as used herein is defined as the novel thin lens of this invention.
The term xe2x80x9carchedxe2x80x9d as used herein is defined as any curved shape which can be made by folding or curving a flat sheet, or by folding or curving a sheet which has at-least one flat surface. For example: half a cylinder (cut through its main axis) will be called herein xe2x80x9can arched shapexe2x80x9d because it can be made from a flat sheet. For purposes herein, folding, curving, and arching are meant the same.
The term xe2x80x9cflatxe2x80x9d as used heroin is not limited to the geometric definition of flat surface (i.e. all the points on the flat sure are on the same geometric plane) but it indicates any abasexe2x80x9d three dimensions structure that by folding or curving it we get a required predetermined shape (which will be called herein xe2x80x9carchedxe2x80x9d shape although it is not made by folding or curving a xe2x80x9cgeometricxe2x80x9d flat sheet).
The term xe2x80x9csaw-toothed surfacexe2x80x9d as used herein is defined as a surface having a plurality of discontinuities. That surface may be characterized by having a saw-toothed surface, and/or having a steps function nature, and/or having a plurality of grooves or protrusions or saw-teeth, and/or may be defined as a surface that contains a plurality of points or lines or zones wherein the surface is not being at least twice continuously differentiable. Herein all these terms are equivalent.
3. Description of Prior Art
In 1748, Count Buffon proposed to grind out of a solid piece of glass a lens in steps or concentric zones, in order to reduce the thickness of the lens to a minimum. In 1822, Augustin Fresnel, for whom the Fresnel lens is named, conducted a lens in which the centers of curvature of the different rings receded from the axis according to their distances from the center.
Modern flat Fresnel lenses consist of a series of concentric prismatic grooves, designed to cooperatively direct incident light rays to a common focus or focuses. This type of lens is thin, lightweight, can be made elastic, shook resistance, and almost unbreakable. Modern flat Fresnel lenses can be inexpensively and accurately mass-produced using known replication techniques. The problem with Modern flat Fresnel lenses is that they are designed to be flat. As a result, when a designer design an eyewear which contains Fresnel lens, one of his considerations must be the lens"" flat shape.
U.S. Pat Nos. 3,698,854 and 3,904,281, each issued to Jampolsky, discloses a thin, fully conformable, planarly smooth, plastic membrane which applied and made to adhere with finger pressure to a conventional spectacle lens. The step quickly changes one or more optical characteristics of the spectacle lens or provides a change in the light transmission across the field of view. Those two patents force a thin flat Fresnel lens, which was designed to be used as a flat lens, to adhere to any light-transmitting element Jampolsky did not disclose a flat Frenel-type lens which is designed especially to be used arched or concaved or convexed. Consequently, when that lens was adhered to the spectacles, there were optical imperfections, distortions, and aberrations visible to the wearer.
In my co-pending PCT Patent Application xe2x80x9cOphthalmic lens synthesized from its specificationsxe2x80x9d, from date Aug. 31, 1998 Number PCT/IL98/00420, I disclosed a lens having very good optical quality that can be made to almost any shape and almost any thickness the designer whishes. That lens can convert any unprescription eyewear to prescription eyewear, and/or manufacture prescription eyewear which has any desired shape, and/or manufacture prescription lenses which are enough thin and flexible to enable people to cut and shape their lenses. In addition, that lens can be laminated.
It was found out that it is less expensive to manufacture a flat saw-toothed lens than to manufacture a not flat saw-toothed lens.
There was a need to develop an ophthalmic lens which is on the one hand as inexpensive as a flat Fresnel lens when mass-manufactured, and on the other hand will not suffer from optical imperfections, distortions and aberrations visible to the wearer when it will be arched. With that inexpensive lens we can convert a large amount of unprescription eyewears to prescription eyewears, or make an inexpensive lens that can be very thin, lightweight, flexible, and unbreakable, in a large variety of arched shapes.
The previous art prescription lenses are rigid and thick. Shaping and cutting those lenses require expensive tools which are not accessible to most of the people. As a result, most of the people don""t have unique eyewears. People cannot cut their lenses to the shape they want, fashioners cannot cut the lenses to shapes that will fit to the dress, the haircut, the car . . . they designed, etceteras, herein after refer to xe2x80x9crecreational stuffxe2x80x9d.
Similarly to lenses, It was found out that it is less expensive to manufacture a flat saw-toothed mirror than to manufacture a not flat saw-toothed mirror. There was a need to develop a mirror which is on the one hand as inexpensive as a flat Fresnel mirror when mass-manufactured, and on the other hand will have an arched shape and will not suffer from optical imperfections and distortions and aberrations visible to the observer.
It is a primary object of the present invention to provide an arched optical surface and more specifically an arched prescription optical surface, such as an arched optical device and arched ophthalmic lens. Novel arched mirrors are also considered a part of this invention. These products are commonly referred to as Flat-Thieberger-design-lenses, including mirrors, that can have almost any desired arched shape.
It is another object of the present invention to provide a less expensive arched Thieberger-design-lens. Most of the design process of Flat-Thieberger-design-lens is similar to the design process of Thieberger-design-lens, but it is manufactured as a flat lens and after or while manufacturing it is folded to the predetermined arched shape. Because flat-Thieberger-design-lens is manufactured as a flat lens, it is usually less expensive than Thieberger-design-lens.
The surface can have any thickness as long it can be arched. There is almost no connection between the thickness and the arched macroscopic shape of flat-Thieberger-design-lens to its optical characteristics
It is another object of the present invention to provide a method which the design is synthesized from its specification. The design method permits generation of different families of arched lenses, embodying different selections of other parameters such as zones size and placement, eye path, etc.
Flat-Thieberger-design-lens has three main preferred embodiments. An Add-on type Flat-Thieberger-design-lens, a Stand-alone type Flat-Thieberger-design-lens, and a composition of the former.
Add-on type Flat-Thieberger-design-lens is bonded or attached to an eyewear that contains an arched lens. Its main purpose is to convert an unprescription arched eyewear to a prescription eyewear or to change one or more optical characteristics of any arched prescription or unprescription optical element, what ever its kind or use.
Add-on Flat-Thieberger-design-lens by itself may also be too thin to provide a desirable degree of impact strength, thus cannot be used individually.
The Add-on Flat-Thieberger-design-lens may cover all the surface of the lens of the eyewear or only a part of it. It may be attached or adhered permanently or impermanently to the front and/or rear surface of the eyewear. It may be used for cost reduction.
The main purpose of the Stand-alone Flat-Thieberger-design-lens is to provide a better alternative to conventional prescription lenses.
It is another object of the present invention to provide an arched prescription lens which may be very light-weight, may be elastic (suitable for instance to sport activities, safety glasses, children""s glasses, etc.), may be almost unbreakable, inexpensively mass-produced, may have large angular viewing range, may have high power and very low aberrations, may be enough thin and soft to enable people to cut and shape their lenses as they wish by using simple cutting accessories such as scissors and the like.
It is another object of the present invention to provide a laminated Flat-Thieberger-design-lens made of two or more layers. Light reflective or polarizing material may be provided between the layers. One of the layers can be provided with photochromic characteristics. That laminated lens has all the economic advantages of the previous art laminated lenses, has all the economic advantages of laminated Thieberger-design-lens, and in addition, has all the economic advantages of Flat-Thieberger-design-lens.
Organic (polymers and plastics) lenses are less fragile, lighter, and more economically mass-manufactured then glass lenses, but are inferior to glass lenses with respect to hardness, scratch resistance, resistance to radiation, ability to receive a wide range of lasting surface treatments (such as anti-reflecting, reflecting, coloration), and photochromic durability.
It is another object of the present invention to provide a high quality laminated arched composite lens, composed of one or more organic Flat-Thieberger-design-layers and an arched glass layer. That composite lens incorporates all the advantages of organic lenses and all the advantages of glass lenses. In addition, it can have highly impact resistance and highly shatter resistance. The organic layer may also be used for correcting aberrations of the glass layer, such as, for example, chromatic aberration.
Flat-Thieberger-design-lens may be combined with conventional stock lenses.
It is another object of the present invention to provide a thin, lightweight, and high quality prescription lenses for patients who have suffered cataract, or some retinal or optic nerve damage which results in decreased visual function due to decreased visual acuity, or decreased visual field, or formation of blind spots, or a combination of thereof. This object can be achieved since the arched prescription lens of the present invention has rough surface, which permit individual calculation of each normal to the prescription lens in such a way that optimal correction can be obtained for each eye viewing angle in the viewing zone, and/or optimal minimization of the residual and peripheral astigmatism and blur can be obtained for each viewing-axis depending on the selected eye model and according to the lens characteristics and profile of use
Flat-Thieberger-design-lens may be partially or entirely tinted to pass or reflect certain wavelengths of light, may be diffused, or blurred uniformly or differentially, may have selective opaque or transmitting areas or a combination thereof, may be coated with polarizing material, may be coated with scratch resistant material, may be coated with anti-static material, may be coated with holographic recording material as disclosed for example in U.S. Pat No. 5,432,623, may be marked as disclosed for example in U.S. Pat. No. 4,619,504.
The prescription parameters (such as eye path location, axis, power, cylinder location, etc.) may be noted on the lens with impermanently ink or on a non-stick protective covering, etc.
In a preferred embodiment, Flat-Thieberger-design-lens is covered with a protective layer which protects its saw-toothed surface against scratches, dust, etc.
It is a further object of the present invention to provide a method that controls on the arched lens"" viewed geometric pattern (caused be the discontinuities of the surface) in purpose to make a more aesthetic and fashioned article, and to enable the designer to optimize to minimum the diffraction aberrations and the image blur and to optimize the manufacturing process.
In order to carry out all the objects of the present invention, the lens"" designer defines the desired arched macroscopic surfaces of the Flat-Thieberger-design-lens (the shape of the lens after folding or curving it to the desired shape). One surface (or both of them) is not smooth but has a microscopic surface that looks like a saw-toothed surface, sometimes refer to as a saw-toothed zone or as a saw-toothed surface zone or as a prescription saw-toothed surface zone (each saw-tooth is smooth of course). The design process assumes that the locations of the object, the lens, and the required image are known. By using Ray-tracing technique we calculate the microscopic normals to the lens"" surface that will form the required image. The final microscopic surface (which looks like a saw-toothed surface) is obtained by a continuously summation of the slopes (which are obtained from the previous calculated microscopic normals to the lens"" surface). Before starting to sum the slopes, we set a set of conditions, which will be called herein xe2x80x9cGeometric pattern conditionsxe2x80x9d or predetermine condition/s. Those conditions may be any one or all of the following: condition on H, geometric condition, diffraction consideration, quality of the formed image, cosmetic factors, grinding technique, manufacturing technique, surface durability, tolerance budgeting methods. Those conditions determine the dimensions of each saw-tooth, i.e., until when the slope summation process will continue and when there will be a discontinuity and a new slope summation for a new saw-tooth will begin. The Geometric Pattern Conditions can determine directly the size or height of the saw-tooth by using a condition on the shape or on the height, or determine indirectly by using a condition on the diffraction effect or the image quality, i.e. the slope summation process will continue until the diffraction effect will get to some predetermined value or the image blur be less than a predetermined value. After setting the xe2x80x9cGeometric pattern conditionsxe2x80x9d we transform the lens"" three dimensions arched shape (including the calculated microscopic normals and the Geometric pattern conditions) to a plane (the lens is flattened). When that flat lens will be folded to the desired arched shape, we will obtain exactly the previous arched shape, with the same microscopic normals to the surface. The final microscopic surface will be obtained by a continuously summation of the transformed slopes in-conjunction with the transformed Geometric pattern conditions.
It is another object of the present invention to provide unifocal and multifocal arched mirrors. Those mirrors can be made flexible.
The novel arched prescription lens of the present invention enable the manufacturer to produce an arched saw-toothed prescription lens that cost the same as a flat saw-toothed prescription lens.
Further objects, features and advantages of the present invention can be more completely understood by reference to the detailed description of preferred embodiments, taken in conjunction with the drawings, and from the appended claims.